I have kind of a secret fetish for good free fonts, so Fonts 500, a site that has collected the top 500 popular fonts used on the Web, is definitely on my good list.

You can preview each font using your own custom text; each font can be downloaded as a zip file quickly and easily. There are five pages of really good fonts here, I don't think I saw any that I didn't like (which presents a problem in itself, I must say).